Kernel oops after sync command in jffs2

Frederic Giasson fgiasson at
Thu May 23 11:36:53 EDT 2002

Hi Ales,

I am currently testing the modifications I suggested in do_write_oneword and
do_erase_oneblock regarding polling.  If you want my sources to test it
and/or improve it yourself, just let me known.  Otherwise, when I will have
tested it throughfully, I will commit it into the CVS tree.


Frédéric Giasson  

|-----Original Message-----
|From: Ales Makarov [mailto:ales.makarov at]
|Sent: Thursday, May 23, 2002 11:34 AM
|To: Frederic Giasson; Linux MTD mailing list
|Subject: Re: Kernel oops after sync command in jffs2
|Frederic Giasson wrote:
|> However, I had a look at do_erase_oneword() function.  I 
|seen that to verify
|I guess you mean do_write_oneword() function.
|> if write operation has completed, we simply read back the 
|written value
|> until it matches or until we read back 10000 times or more.  
|This works most
|> of the time, but in my opinion it is not the best way to do that.
|You are right. This could be my problem...
|> What I think we should do to determine if write operation 
|has completed OK
|> is to poll DQ6 and DQ5, as we do for erase operation.  However, since
|> program operation takes *much* less time than erase 
|operation ( 150 us max
|> accoring to my AMD spec ), we should not schedule.  We 
|should simply poll
|> 150 times at most, inserting a "udelay(1);" in each loop.  
|If DQ5 rises, we
|> must threat it the same way we do in do_erase_oneblock().
|I agree. I would also prefer the DQ6 and DQ5 testing.
|> Also, speaking of do_erase_oneblock(), it is said in my AMD 
|spec that when
|> DQ5 rises, even if that happen while DQ6 still toggle, it is 
|necessary to
|> read DQ0-DQ7 twice once again and compare both values to see 
|if it still
|> toggles.  If it does not toggle, it means that erase 
|operation has completed
|> correctly.  You can verify that my yourself by having a look 
|at figure 6, p.
|> 29 in spec sheet "Am29DL322D/323D/324D, revD, May 8th, 2001".
|> Frederic Giasson
|I have read it also in the datasheet of the Fujitsu MBM29LV320 (p.32).
|These additional reads should be done, because the toggle bit may have
|stopped toggling just as DQ5 went high.

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